Secondary Orbital Tumours and Orbital Metastases

Secondary orbital tumours are lesions that originate from contiguous structures such as the eyelids, conjunctiva, eye, paranasal sinuses, nasopharynx, and that grow large enough to invade the orbit. Metastatic orbital tumours are those that spread to the orbit by blood from distant foci. Basal cell eyelid carcinoma (BCC) and squamous cell conjunctival carcinoma are the two most frequent tumours which can lead to a secondary orbital invasion. BCCs invading the orbit have been successfully treated in recent years with medications that target the sonic hedgehog pathway. Epidermal growth-factor receptor (EGFR) inhibitors are effective for treatment of patients with locally advanced or metastatic squamous cell carcinoma of the head and neck, although exenteration may be considered in patients with orbital involvement and poor residual visual acuity. Most orbital metastases are carcinomas, sarcomas and melanomas being considerably less common. Breast is the most common primary site of metastatic orbital lesions, followed by lung and prostate. Treatment of orbital metastatic lesions may help to control the growth of the tumour, to preserve visual function and to improve patient comfort. There is no standard treatment: surgery, radiotherapy or neoadjuvant therapy may have favourable responses, although the prognosis usually remains poor.